If Mary earns $80,000 in taxable income and pays $40,000 in taxes, her marginal tax rate must be 50 percent.

Which of the following is correct as it relates to cost curves?

A) Average variable cost intersects marginal cost at the latter's minimum point.
B) Marginal cost intersects average total cost at the latter's minimum point.
C) Average fixed cost intersects marginal cost at the latter's minimum point.
D) Marginal cost intersects average fixed cost at the latter's minimum point.